Non-insulin dependent diabetes mellitus (NIDDM) is a major source of morbidity and mortality in the United States, affecting 13-16 million Americans. Women appear to be dis-proportionately affected, with particularly high prevalence and associated morbidity among African- American women. Obesity has been implicated as a primary factor in the etiology of NIDDM and weight loss is recommended as a principal intervention for obese diabetic individuals. Although behavioral obesity treatments produce weight losses and improve glycemic control, they have achieved only modest long-term success, particularly among African- American women. Our pilot data indicate that the addition of motivational interviewing methods to a behavioral weight control program enhanced the short-term treatment efficacy of in achieving glycemic control for older women with NIDDM. Thus, the overall objective for this proposed 5-year project is to determine whether the addition of motivational interviewing to a behavioral weight control program for NIDDM produces significantly greater long-term improvements in glycemic control and weight loss than a standard behavioral weight control program in a sample of black and white women. We propose to recruit a total of 218 women (84 African-American women) aged 40 or older with NIDDM who are overweight (body mass index between 27 and 45). Participants will randomized to one of two treatment conditions within race: l) behavioral weight control with motivational interviewing (BT+MI); or 2) behavioral weight control with health education attention control (BT+HE). Primary outcome measures to evaluate treatment efficacy will be glycemic control (HbA1c and weight loss at 6-, 12- and 18-month follow-up. Secondary measures obtained at each assessment point will include: 1) treatment adherence (e.g., group attendance, self-monitoring, dietary' change, physical activity, and medication adherence); 2) change in cardiovascular disease (CVD) risk factors (e.g., insulin resistance, fat distribution, lipids, and blood pressure); 3) mood and attitudinal measures; and 4) quality of life.